Scientists Decipher Cholera Microbe Makeup

Researchers have deciphered the genetic makeup of one of
humanity’s oldest, deadliest and hardiest adversaries — the cholera
microbe.

Scientists say the research may help spur new vaccines or drugs
to treat cholera, one of the most efficient killers of all
diseases.

“This will be the starting point for most future studies,”
said microbiologist Matthew Waldor of Tufts Medical School in
Boston. He co-wrote an accompanying commentary on the research,
which was being published Thursday in the journal Nature.

Researchers at The Institute for Genomic Research in Rockville,
Md., led the study team that successfully analyzed the entire
genetic structure of the bacterium Vibrio cholerae.

They found that the germ carries two chromosomes with a total of
3,885 genes. They are formed from about 4 million chemical building
blocks known as base pairs.

The researchers identified the genes by chemically breaking up
strands of the germ’s DNA. They analyzed the fragments separately
and later figured out how to reassemble them in order. Similar
techniques have been used to identify the genes of other disease
microbes and humans.

A 2,000-Year-Old Disease

Cholera, which has afflicted humans for more than 2,000 years,
is largely eradicated from the United States and other industrial
nations. Yet epidemics still plague parts of Asia, Africa and Latin
America, where water supplies are often contaminated. More than
220,000 cases were reported to the World Health Organization last
year, with over 8,400 deaths. Tens of thousands have died in some
epidemic years.

The bacterium, which can live in brackish water and estuaries,
attacks the intestine of humans and can cause death by severe
dehydration.

Claire Fraser, director of the institute, said the knowledge of
cholera’s genes is most likely useful in developing vaccines. They
now exist but confer immunity only for several months.

Fraser added, though, that even knowing the genetic makeup, it
is an “unrealistic goal” to wipe out cholera.